UWL: Food, Appetite and Environment (2009)
Citation:
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
- To evaluate the effect of replacing the "traditional" dinner with carbohydrate on overall food intake in nursing home residents with Alzheimer's disease
- To identify participant characteristics, such as carbohydrate preference, BMI, cognitive and behavioral function and the presence of behavioral problems, that were associated with intervention response.
Inclusion Criteria:
Nursing home residents with probable Alzheimer's disease who ate independently.
Exclusion Criteria:
- Diseases requiring nutritional intervention
- Prescription of an energy-restricted diet
- Swallowing difficulties requiring texture-modified foods
- Unplanned weight loss (loss of 10% or more during the six months before start of study or 5% or more during previous month)
- Acute illness.
Description of Study Protocol:
- Recruitment: Residents of the Alzheimer's Disease units of Baycrest Centre for Geriatric Care nursing home, a kosher facility.
- Design: Randomized crossover trial.
- Blinding used: Non-blinded.
Intervention
- Replacing 12 non-consecutive "traditional" dinners with meals high in carbohydrate, but comparable to traditional dinners in protein
- Four phases, each lasting 21 days
- Phase One: Usual diet
- Phase Two: Random assignment to high-carbohydrate dinner or mid-morning nutrition supplement intervention
- Phase Three: Usual diet washout period
- Phase Four: Received opposite treatment.
Statistical Analysis
- Power analysis required 28 participants
- Mean intervention vs. baseline energy, protein, fat and carbohydrate, were compared using the Student's T-test at both the group level and for each participant
- Comparisons limited to days having dairy dinners
- Habitual macronutrient preference calculated during baseline phase
- Several regression approaches and factor analysis completed.
Data Collection Summary:
Timing of Measurements
Four phases, each lasting 21 days. Body weight measured on Day One and on the last day of every phase.
Dependent Variables
- Weighed food intake
- Body weight and BMI
- Cognitive function assessed using the Severe Impairment Battery and Global Deterioration Scale
- Behavioral disturbances assessed using the Neuropsychiatric Inventory-Nursing Home Version
- Behavioral function assessed using the London Psychogeriatric Rating Scale.
Independent Variables
- "Traditional" dinners vs. meals high in carbohydrate, but comparable in protein
- All foods served to participants were weighed before and after consumption and converted to nutrient intake using software program.
Description of Actual Data Sample:
- Initial N: 34 residents, 27 women, seven men
- Attrition (final N): 32 residents; two dropped out due to acute illness.
- Age: 88.2±3.9 years
- Ethnicity: Not mentioned
- Anthropometrics: Crossover study; no significant differences in subjects during different study phases
- Location: Canada.
Summary of Results:
Other Findings
- Group mean dinner and 24-hour energy intake increased during the intervention phase compared with baseline, protein and fat intake was unaffected and carbohydrate intake increased
- Group mean intake was increased 119.4±115.5kcal at dinner (P<0.001) and 109.6±141.8kcal over 24 hours (P<0.001). There were no changes at other meals.
- Increased dinner intake, attributable to intervention foods, was achieved in 20 of 32 participants and was associated with increased carbohydrate preference, poorer memory and increased aberrant motor behavior
- Those with low BMI were the most resistant to the intervention
- There were no significant changes in body weight during the intervention (increase of 0.36±1.12kg, P=0.076) possibly because of the short intervention period.
Author Conclusion:
Providing a high-carbohydrate meal for dinner increases food intake in seniors at later stages of the disease who are experiencing cognitive and behavioral difficulties, possibly as a result of a shift in preference for high-carbohydrate foods.
Funding Source:
Reviewer Comments:
- Mid-morning nutrition supplement described elsewhere
- Only residents from one nursing home, small sample size
- Kosher meals may have complicated the intervention
- Authors note that further studies evaluating the long-term response to the intervention are needed, as well as the limited generalizability of results.
Quality Criteria Checklist: Primary Research
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Relevance Questions | |||
1. | Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) | Yes | |
2. | Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? | Yes | |
3. | Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? | Yes | |
4. | Is the intervention or procedure feasible? (NA for some epidemiological studies) | Yes | |
Validity Questions | |||
1. | Was the research question clearly stated? | Yes | |
1.1. | Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? | Yes | |
1.2. | Was (were) the outcome(s) [dependent variable(s)] clearly indicated? | Yes | |
1.3. | Were the target population and setting specified? | Yes | |
2. | Was the selection of study subjects/patients free from bias? | ??? | |
2.1. | Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? | Yes | |
2.2. | Were criteria applied equally to all study groups? | Yes | |
2.3. | Were health, demographics, and other characteristics of subjects described? | Yes | |
2.4. | Were the subjects/patients a representative sample of the relevant population? | ??? | |
3. | Were study groups comparable? | Yes | |
3.1. | Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) | Yes | |
3.2. | Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? | Yes | |
3.3. | Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) | Yes | |
3.4. | If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? | N/A | |
3.5. | If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) | N/A | |
3.6. | If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? | N/A | |
4. | Was method of handling withdrawals described? | Yes | |
4.1. | Were follow-up methods described and the same for all groups? | Yes | |
4.2. | Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) | Yes | |
4.3. | Were all enrolled subjects/patients (in the original sample) accounted for? | Yes | |
4.4. | Were reasons for withdrawals similar across groups? | N/A | |
4.5. | If diagnostic test, was decision to perform reference test not dependent on results of test under study? | N/A | |
5. | Was blinding used to prevent introduction of bias? | Yes | |
5.1. | In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? | No | |
5.2. | Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) | Yes | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | N/A | |
5.4. | In case control study, was case definition explicit and case ascertainment not influenced by exposure status? | N/A | |
5.5. | In diagnostic study, were test results blinded to patient history and other test results? | N/A | |
6. | Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? | ??? | |
6.1. | In RCT or other intervention trial, were protocols described for all regimens studied? | No | |
6.2. | In observational study, were interventions, study settings, and clinicians/provider described? | N/A | |
6.3. | Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? | ??? | |
6.4. | Was the amount of exposure and, if relevant, subject/patient compliance measured? | Yes | |
6.5. | Were co-interventions (e.g., ancillary treatments, other therapies) described? | No | |
6.6. | Were extra or unplanned treatments described? | N/A | |
6.7. | Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? | Yes | |
6.8. | In diagnostic study, were details of test administration and replication sufficient? | N/A | |
7. | Were outcomes clearly defined and the measurements valid and reliable? | Yes | |
7.1. | Were primary and secondary endpoints described and relevant to the question? | Yes | |
7.2. | Were nutrition measures appropriate to question and outcomes of concern? | Yes | |
7.3. | Was the period of follow-up long enough for important outcome(s) to occur? | ??? | |
7.4. | Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? | Yes | |
7.5. | Was the measurement of effect at an appropriate level of precision? | Yes | |
7.6. | Were other factors accounted for (measured) that could affect outcomes? | Yes | |
7.7. | Were the measurements conducted consistently across groups? | Yes | |
8. | Was the statistical analysis appropriate for the study design and type of outcome indicators? | Yes | |
8.1. | Were statistical analyses adequately described and the results reported appropriately? | Yes | |
8.2. | Were correct statistical tests used and assumptions of test not violated? | Yes | |
8.3. | Were statistics reported with levels of significance and/or confidence intervals? | Yes | |
8.4. | Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? | N/A | |
8.5. | Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? | Yes | |
8.6. | Was clinical significance as well as statistical significance reported? | Yes | |
8.7. | If negative findings, was a power calculation reported to address type 2 error? | Yes | |
9. | Are conclusions supported by results with biases and limitations taken into consideration? | Yes | |
9.1. | Is there a discussion of findings? | Yes | |
9.2. | Are biases and study limitations identified and discussed? | Yes | |
10. | Is bias due to study's funding or sponsorship unlikely? | Yes | |
10.1. | Were sources of funding and investigators' affiliations described? | Yes | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |